It is well known that desalination plants present a corrosive environment due to the presence of concentrated brine and elevated operating temperatures. This corrosive environment can be detrimental to many of the materials used in these types of plants which would adversely affect plant operations by requiring excessive plant maintenance and repair.
The joints of the heat exchangers in these desalination plants are especially susceptible to corrosion. That is, if the tube joint is not fully sealed, the concentrated brine solution can seep into the resultant crevices and cause excessive corrosion, especially on the relatively thin wall tube.
Presently, heat exchanger tube joints are often manufactured using smooth surfaced tubes and roll expansion. A leak free joint usually results from expansion of smooth O.D. tube into a smooth walled hole in a tube sheet. Although fluted tubes provide beneficial heat transfer characteristics, fluted ended tubes have not been used in these types of applications in part because a pressure tight, corrosion resistant joint has not been designed using fluted tube.
In view of the disadvantages associated with adapting smooth tube joining technology to fluted tubes, a need has developed to provide an improved joint structure which provides an adequate seal between the fluted tube end and the tube receiving opening while maintaining the ability to use a grooved or fluted tube design.
In response to this need, the present invention provides a tube joint construction which provides a leakproof seal and minimizes corrosion at the joint area and is adapted for heat exchanger use, in particular, desalination plant heat exchangers.